Stem cells have evoked considerable excitement in the animal-owning public because of the promise that stem cell technology could deliver tissue regeneration for injuries for which natural repair mechanisms do not deliver functional recovery and for which current therapeutic strategies have minimal effectiveness. This review focuses on the current use of stem cells within veterinary medicine, whose practitioners have used mesenchymal stem cells (MSCs), recovered from either bone marrow or adipose tissue, in clinical cases primarily to treat strain-induced tendon injury in the horse. The background on why this treatment has been advocated, the data supporting its use and the current encouraging outcome from clinical use in horses treated with bone-marrow-derived cells are presented together with the future challenges of stem-cell therapy for the veterinary community.